title: Incidence of cutaneous sebaceous carcinoma and risk of associated neoplasms: insight into Muir-Torre syndrome.
abstract: BACKGROUND
  Sebaceous tumors of the skin occurring in association with an internal malignancy characterize Muir-Torre syndrome (MTS), a variant of hereditary nonpolyposis colon cancer (Lynch syndrome). To the authors' knowledge, only limited information exists regarding incidence patterns of sebaceous carcinoma (SC), and no prior study has quantified risks of associated cancers.
  
  
  METHODS
  The authors calculated cutaneous SC incidence rates (IRs) and IR ratios in 9 US Surveillance, Epidemiology, and End Results program registries (1973-2003). Indirectly standardized incidence ratios and 95% confidence intervals (95% CIs) were calculated for subsequent cancers among 2-month survivors of SC and for subsequent SC after other primary cancers.
  
  
  RESULTS
  Among 664 cases of cutaneous SC, nearly 90% were diagnosed among whites (IR, 0.11 per 100,000 person-years), with significantly lower IR noted among blacks (IR, 0.04). Whereas eyelid SC IRs demonstrated no sex differences and stabilized in recent years, IRs of noneyelid SC predominated in men and rose steadily over time. Survivors of SC had a 43% (95% CI, 15%-76%) increased risk of subsequent cancer, and risk of SC was elevated by 52% (95% CI, 24%-84%) among survivors of other cancers. Whether before or after SC, the significant excesses of other primary cancers were limited to noneyelid SC. Patterns suggestive of genetic predisposition included >20-fold risks for early-onset (diagnosed in patients aged <50 years) SC associated with colon, pancreatic, ovarian, or uterine corpus cancers, whereas late-onset SC (diagnosed in patients aged > or =50 years) predisposed to ureter cancer.
  
  
  CONCLUSIONS
  This population-based study of cutaneous SC revealed an association with a spectrum of early-onset cancers consistent with MTS. Etiologic heterogeneity was suggested by differences between eyelid and noneyelid SC in incidence patterns and associated cancer risks.
authors.affiliation: Medical Service, Department of Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA. doresg@mail.nih.gov
authors.forename: Graça M
authors.initials: GM
authors.lastname: Dores
authors.forename: Rochelle E
authors.initials: RE
authors.lastname: Curtis
authors.forename: Jorge R
authors.initials: JR
authors.lastname: Toro
authors.forename: Susan S
authors.initials: SS
authors.lastname: Devesa
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Fraumeni
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D005142:Eyelid Neoplasms / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D055653:Muir-Torre Syndrome / Q000150:complications*; D018294:Neoplasms, Adnexal and Skin Appendage / Q000453:epidemiology*; D009378:Neoplasms, Multiple Primary / Q000453:epidemiology; D012306:Risk; D018426:SEER Program; D012878:Skin Neoplasms / Q000453:epidemiology*